I copied this from my site blog but I though it was worth repeating here.I'm thinking that you have to work a lot harder to say what you want just using one pencil than you do if using colour and mass. With colour and paint (mass technique) you have the materials which give you more language to use to convey your message, and therefore less imagination is need on the part of the viewer, but you then have more language to master to construct a meaningful conversation. While I was drawing in Belgique I had a chat about the attributes of pencil work with one of the woodford festival volunteers. She said "I prefer looking at pencil drawings, I know paint is good but I think pencil is more human, I mean, everyone knows what a pencil is and you can see the rubbings out." Couldn't agree more.